Polyolefins having unique structures can be made by polymerization with certain late transition metal catalysts. The novel polyolefins have large amounts of branching of all lengths, as a result of which many properties such as molecular size in solution and viscosity are different than for xe2x80x9cformalxe2x80x9d polyolefins.
Addition polymerization of olefins can be accomplished by many methods depending on the olefin(s) to be polymerized. Methods such as coordination polymerization and radical polymerization have been employed. For the most part, these yield polymers which are often linear or contain a small amount of short and sometimes long chain branching. It is well known in the art that the presence of branching alters the properties of the polymer produced, for example low density polyethylene, which is made by high pressure free radical polymerization and contains some short and long chain branching, has a lower melting point and density and different processing characteristics than high density polyethylene which is linear and made by coordination polymerization. Both are important commercial products.
It has recently been reported (see for instance World Patent Application 96/23010, equivalent to U.S. patent application Ser. No. 590,650, filed Jan. 24,1996, both of which are hereby included by reference) that certain late transition metal catalysts can produce polyolefins which have short chain branching, sometimes extensive, which is not due simply to branches caused by the alkyl groups on, for instance, xcex1-olefins. Indeed it is reported that these polyolefins often have more or less short branches than one would expect from the typical polymerization with Ziegler-Natta or metallocene type catalysts. While it is stated that this short chain branching leads to many changes in properties for these polyolefins, such as different melting points and densities, there is no mention that it also leads to large changes in the overall polymer structure (polymer topology) which can affect other polymer properties.
It is known in the art that differing branching in polymers leads to property changes, see for instance F. W. Billmeyer, Textbook of Polymer Science, 3rd Ed., John Wiley and Sons, New York, 1984, chap. 8 and 11; P. J. Flory, Principles of Polymer Chemistry, Cornell University Press, 1953, chap. 7; and C. Tanford, Physical Chemistry of Macromolecules, John Wiley and Sons, New York, 1961, chap. 6 and 9, all of which are hereby included by reference. For instance, it is well known that long chain branching can affect bulk polyolefin viscosities to the point that some long chain branching is sometimes deliberately introduced into otherwise linear (except perhaps for short chain branching) polyolefins to alter their bulk melt behavior. This is usually done by the introduction of small amounts (larger amounts normally lead to crosslinking) of a difunctional monomer which acts as a branch point in the polyolefin molecule.
Therefore the ability to provide polyolefins with large amounts of branching, especially long chain branching is desired. However one normally wishes to accomplish this without unduly increasing the molecular weight of the polyolefin (as occurs before crosslinking) or actually crosslinking the polyolefin.
This invention concerns a polyolefin, wherein a root mean square radius of a molecule of said polyolefin in tetrahydrofuran solution is:
less than 40 nm at a molecular weight of 1,000,000 Dalton; or
less than 15 nm at a molecular weight of 100,000 Dalton;
and provided that:
said polyolefin is composed of repeat units derived from one or more olefins of the formula H2C=CHR1, wherein R1 is hydrogen, hydrocarbyl, substituted hydrocarbyl or a functional group.
This invention concerns a polyolefin, wherein an intrinsic viscosity of said polyolefin in tetrahydrofuran solution is:
less than 3.0 dL/g nm at a molecular weight of 1,000,000 Dalton; or
less than 0.80 dL/g at a molecular weight of 100,000 Dalton; or
less than 0.25 dL/g at a molecular weight of 10,000 Dalton;
and provided that:
said polyolefin is composed of repeat units derived from one or more olefins of the formula H2Cxe2x95x90CHR1, wherein R1 is hydrogen, hydrocarbyl, substituted hydrocarbyl or a functional group.
This invention also concerns a polyolefin, wherein a root mean square radius of a molecule of said polyolefin in tetrahydrofuran solution is described by the equation:
Rg=A(MB)
wherein:
Rg is said root mean square radius in nm;
A is a constant;
M is a molecular weight of said molecule; and
B is a constant whose value is about 0.50 or more;
and provided that:
said polyolefin is composed of repeat units derived from one or more olefins of the formula H2Cxe2x95x90CHR1, wherein R1 is hydrogen, hydrocarbyl, substituted hydrocarbyl or a functional group.
Also described herein is a polyolefin, wherein Mark-Houwink constants are measured by size exclusion chromatography/viscometry in tetrahydrofuran and calculated according to the equation
[xcex7]=KMxcex1
wherein:
[xcex7] is an intrinsic viscosity in tetrahydrofuran of said polyolefin of molecular weight M;
M is a molecular weight of said polyolefin;
xcex1 is about 0.60 or less;
and provided that:
said polyolefin is composed of repeat units derived from one or more olefins of the formula H2Cxe2x95x90CHR1, wherein R1 is hydrogen, hydrocarbyl, substituted hydrocarbyl or a functional group.